I am getting some front end body work done on my E320. After it was put back together the drivers side headlight wiper started running backward i.e. wiping down toward the bumper instead of across the headlight. The dealer examined it and says there are 2 passenger side wiper motors on the car but I am told that the wiper motors were not changed out. Is there a way that the polarity could have gotten switched on the motor?

 

Check the numbers on both motors.And check the wires.Brown is usually ground.Maybe they plugged in the wires wrong.